Polycarbonate compositions having improved adhesion to polyurethane layers

ABSTRACT

The present invention relates to compositions
     and composite components formed from these compositions and a polyurethane layer, which are notable for improved adhesion between the two layers,   and a process for producing the composite components.

The present invention provides polycarbonate compositions havingimproved adhesion to polyurethane systems, composite systems comprisingthese polycarbonate compositions and polyurethane systems, and alsoshaped bodies formed from these composite systems and processes forproducing the composite systems. The polycarbonate compositions arenotable not only for improved adhesion to the polyurethane system butalso for constantly high toughness, high heat distortion resistance andexcellent flame retardancy.

WO 2006/072366 A1 describes a process for forming and coating asubstrate in a mould having at least two cavities. The process comprisesthe steps of:

a) forming a substrate in a first cavity of the mould,

b) introducing the substrate produced in the previous step into a secondcavity of the mould and

c) coating the substrate in the second cavity with a coating material,the coating being effected under elevated pressure.

By way of example and with preference, polyurethane coating materialsand PC+ABS substrates (polycarbonate+acrylonitrile-butadiene-styrenesubstrates) are mentioned. No pointers are given in this application asto the influence of the carrier material composition on the adhesiveproperties of the material composite.

EP 2089207 A1 discloses a process for producing a composite component,especially comprising an injection moulding and a polyurethane element,comprising the steps of

-   a) producing a carrier component,-   b) moving or transferring the carrier component to an opened cavity    of a mould,-   c) closing the mould to a predetermined position, creating an    enlarged cavity having a first size,-   d) generating a reduced pressure in the enlarged cavity of the first    size,-   e) introducing a flooding material into the enlarged cavity and-   f) conducting an embossing step simultaneously with the introduction    and/or after the introduction of the flooding material, while at    least slightly reducing the size of the cavity.

For improvement of the composite adhesion, activation of the surface ofthe thermoplastic by flaming, plasma treatment or gas is described here.No pointers are given in this publication as to the influence of thecarrier material composition on the adhesion properties of the materialcomposite.

DE 10 2006 033 059 A1 discloses a process for producing plastic interiorcomponents. In this process, in a first step, the carrier is formed in afirst mould, then the first mould is at least partly replaced by asecond mould and then the top layer is formed on the carrier in a secondstep. The carrier material used is a hard component, e.g. PA+ABS blends(polyamide+acrylonitrile-butadiene-styrene) or PC+ABS blends(polycarbonate+acrylonitrile-butadiene-styrene), and the top layer usedis a soft component, preferably polyurethane foam. No pointers are givenin the application as to the influence of the composition of the carriermaterials on the composite properties of the components thus produced.Instead, DE 10 206 033 059 A1 likewise proposes improving the adhesionby preparing the surface by primers or by laser, corona or plasmatreatment.

WO 99/20464 A1 discloses composites of at least two different polymermaterials bonded directly to one another: a) a thermoplastic polymer ora thermoplastic mixture of polymers which contain at least one polarcompound of at least one of the metals of main groups 1 to 5 or oftransition groups 1 to 8 of the Periodic Table as ultrafinelydistributed inorganic powder and b) polyurethane present in the form ofa foam, coating material or compact material. No adhesion promoter layeris required for the composite. No pointers are given in this publicationwith regard to the influence of the carrier material composition interms of ABS content and rubber content on the adhesion properties ofthe material composite.

DE 101 09 226 A1 discloses a polycarbonate composition comprising a)aromatic polycarbonate and/or polyester carbonate, b) graft polymer andc) copolymer of styrene and a monomer containing carboxyl groups, wheresaid copolymer has a mean molecular weight Mw of >=10 500 g/mol, andwhere said copolymer may contain one or more vinyl monomers. Component Cis preferably a copolymer of styrene and maleic anhydride. DE 101 09 226A1 further discloses composite components comprising at least one firstlayer (1) and a second layer (2), in which layer (1) includes at leastone polycarbonate composition (as specified in a, b and c) and layer (2)contains at least one polyurethane. It is a feature of the compositethat the decrease in foam adhesion between layer (1) and layer (2) is atmost 35% after a double alternating climate test. No pointers are givenin this publication as to the influence of the carrier materialcomposition in terms of ABS content and rubber content on the adhesionproperties of the material composite.

EP 0 363 608 A1 discloses polymer mixtures comprising polycarbonate, astyrene-containing copolymer and/or a styrene-containing graft polymerand a flame retardant. Through the use of oligomeric phosphates as flameretardant, a good combination of properties of flame retardancy, lowmigration of the flame retardant to the component surface, goodplasticizing action and good heat distortion resistance is achieved.There is no disclosure about adhesion properties with regard topolyurethane systems.

US 2012/0053271 A1 discloses compositions comprising polycarbonate,polyester, rubber-modified graft polymer and optionally flameretardants, further polymers and additives. The compositions featuregood mechanical properties and low shrinkage. The properties that areadvantageous over the prior art cited in this application are achievedthrough particular polyesters having a proportion of isophthalic acidunits. There is no disclosure about adhesion properties with regard topolyurethane systems.

It was an object of the present invention to provide polycarbonatecompositions having improved adhesion to polyurethane systems, compositesystems comprising these polycarbonate compositions and polyurethanelayers, and shaped bodies formed from these composite systems.Polycarbonate compositions should be notable for improved adhesion tothe polyurethane system, and for a constantly high toughness, high heatdistortion resistance and excellent flame retardancy. More preferably,the moulding compositions are to have a Vicat temperature exceeding 100°C.

In addition, a process for producing these composite components is to beprovided.

The polyurethane layer may serve, for example, to improve the surfaceproperties, for example scratch resistance, self-healing, weatheringstability, tactile properties, optical properties, sound insulation andthermal insulation, of the composite components.

The object of the present invention is achieved by polycarbonatecompositions comprising

A) 70 to 95 parts by weight, preferably 72 to 95 parts by weight, morepreferably 73 to 95 parts, by weight of at least one polymer selectedfrom the group consisting of aromatic polycarbonate and aromaticpolyester carbonate,

B) 1 to 10 parts by weight, preferably 2 to 10 parts by weight, morepreferably 3 to 10 parts by weight, of a mixture comprising at least onepolybutadiene-based graft polymer and at least one butadiene-free vinyl(co)polymer,

C) 1 to 20 parts by weight, preferably 2 to 19 parts by weight, morepreferably 2 to 18 parts by weight, of at least onephosphorus-containing flame retardant selected from the group consistingof phosphonate amines, phosphazenes and monomeric and oligomericphosphoric and phosphonic esters of the general formula (V)

-   -   in which    -   R¹, R², R³ and R⁴ are each independently optionally halogenated        C₁ to C₈-alkyl, in each case optionally alkyl-substituted,        preferably C₁ to C₄-alkyl-substituted, and/or        halogen-substituted, preferably chlorine- or        bromine-substituted, C₅ to C₆-cycloalkyl, C₆ to C₂₀-aryl or C₇        to C₁₂-aralkyl,    -   n is independently 0 or 1    -   q is 0 to 30

X is a polycyclic aromatic radical having 12 to 30 carbon atoms, or alinear or branched aliphatic radical having 2 to 30 carbon atoms, whichmay be OH-substituted and may contain up to 8 ether bonds,

D) 0.1 to 20.0 parts by weight, preferably 0.2 to 15 parts by weight,more preferably 0.3 to 10 parts by weight (based in each case on the sumtotal of components A to C), of at least one polymer additive,

where the polybutadiene content based on the sum total of the parts byweight of components A to C is 0.5% to 5.5% by weight, preferably 1.0%to 5.5% by weight, more preferably 1.5% to 5.5% by weight,

and where the total content of butadiene-free vinyl (co)polymer fromcomponent B based on the sum total of components A to C is 0.5% to 5.0%by weight, preferably 0.5% to 4.5% by weight, more preferably 1.0% to4.5% by weight,

and where the compositions are free of thermoplastic polyesters such aspolyalkylene terephthalates,

and where the sum total of the parts by weight of components A, B and Cin the polycarbonate composition is normalized to 100.

While the ranges of preference mentioned can be combined freely with oneanother, preference is given to combining the respective first, middleand last ranges with one another.

In a further preferred embodiment, the polycarbonate compositions arefree of fillers and reinforcers, for example talc, glass fibres orcarbon fibres (optionally including ground fibres), (hollow) glass orceramic beads, mica, kaolin, CaCO₃ and glass flakes.

In a further preferred embodiment, the polycarbonate compositionscomprise

A) 70 to 95 parts by weight of at least one polymer selected from thegroup consisting of aromatic polycarbonate and aromatic polyestercarbonate,

B) 1 to 10 parts by weight of a mixture comprising at least onepolybutadiene-based graft polymer and at least one butadiene-free vinyl(co)polymer,

C) 1 to 20 parts by weight of a phosphorus-containing flame retardant ofthe formula Va

D) 0.1 to 20.0 parts by weight (based in each case on the sum total ofcomponents A to C) of at least one polymer additive,

where the polybutadiene content based on the sum total of the parts byweight of components A to C is 0.5% to 5.5% by weight,

and where the total content of butadiene-free vinyl (co)polymer fromcomponent B based on the sum total of components A to C is 0.5% to 5.0%by weight,

and where the graft polymer of component B, based on the graft polymer,comprises 25% to 60% by weight of at least one vinyl monomer and 75% to40% by weight of one or more polybutadiene-based graft bases,

and where the graft base of the polybutadiene-based graft polymer has amedian particle size (d₅₀) of 0.2 to 1.0 μm, measured by ultracentrifugemethodology,

and where the compositions are free of thermoplastic polyesters such aspolyalkylene terephthalates,

and where the sum total of the parts by weight of components A, B and Cin the polycarbonate composition is normalized to 100.

In a further preferred embodiment, the polycarbonate compositionscomprise

A) 73 to 95 parts by weight of at least one polymer selected from thegroup consisting of aromatic polycarbonate and aromatic polyestercarbonate,

B) 3 to 10 parts by weight of a mixture comprising at least onepolybutadiene-based graft polymer and at least one butadiene-free vinyl(co)polymer,

C) 2 to 18 parts by weight of a phosphorus-containing flame retardant ofthe formula Va

D) 0.3 to 10 parts by weight (based in each case on the sum total ofcomponents A to C) of at least one polymer additive,

where the polybutadiene content based on the sum total of the parts byweight of components A to C is 1.5% to 5.5% by weight,

and where the total content of butadiene-free vinyl (co)polymer fromcomponent B based on the sum total of components A to C is 1.0% to 4.5%by weight,

and where the graft polymer of component B, based on the graft polymer,comprises 25% to 60% by weight of at least one vinyl monomer and 75% to40% by weight of one or more polybutadiene-based graft bases,

and where the graft polymer is prepared by emulsion polymerization

and where the graft base of the polybutadiene-based graft polymer has amedian particle size (d₅₀) of 0.2 to 0.5 μm, measured by ultracentrifugemethodology, and where the compositions are free of thermoplasticpolyesters such as polyalkylene terephthalates.

In a preferred embodiment, the polycarbonate compositions consist onlyof components A, B, C and D.

In addition and with preference, the object of the present invention isachieved by composite components comprising

-   -   a) a carrier composed of a polycarbonate composition as        specified above    -   b) at least one polyurethane layer.

Said polyurethane layer may, for example, be a PU coating material, a PUfoam or else a compact PU skin having polyurethane layer thicknesses of,for example, 1 μm up to 20 cm.

In a preferred embodiment, the polyurethane layer is a coating materialhaving a layer thickness of 1-1000 μm, further preferably 10-500 μm andmore preferably 50-300 μm.

In a further preferred embodiment, the polyurethane layer is a foamhaving a layer thickness of 1 mm-20 cm, further preferably 1 mm-10 cmand more preferably 1 mm-1 cm.

In a further preferred embodiment, the polyurethane layer is a compactskin having a layer thickness of 0.5 mm-10.0 mm, preferably 0.5 mm-5.0mm and more preferably 1.0 mm-4.0 mm.

The composite components can in principle be produced in any knownmanner.

Preferably, the polyurethane layer is produced by full polymerization ofa reactive polyurethane raw material mixture comprising

-   -   at least one polyisocyanate component,    -   at least one polyfunctional H-active compound, and    -   optionally at least one polyurethane additive and/or processing        aid,

in direct contact with the carrier which has been shaped beforehand fromthe thermoplastic composition and solidified.

The carrier component may be prefabricated, for example, from thethermoplastic PC+ABS composition and the reactive polyurethane rawmaterial mixture may be applied thereto and reacted fully. According tothe reactivity of the polyurethane reaction components, they may alreadyhave been premixed or may be mixed in a known manner during theapplication. The application can be effected by methods includingspraying, knife-coating or calendering.

If foamed composites are to be produced, it is possible in a mannerknown per se to introduce the reaction mixture into a mould containingthe previously formed and solidified support component. Optionally, themould may also contain a further decorative layer (often called “skin”)composed of, for example, polyvinyl chloride (PVC), thermoplasticpolyolefins (TPO), thermoplastic polyurethane (TPU) or sprayablepolyurethane skin. In the mould, the foamable reaction mixture foams incontact with the carrier component and any decorative layer, and formsthe composite component. The in-mould foaming can be performed in such away that the composite component has a cell structure at its surface.Alternatively, it can be conducted in such a way that the compositecomponent has a compact skin and a cellular core (integral foams). Thepolyurethane components can be introduced into the mould withhigh-pressure or low-pressure machines. Polyurethane foams can also beproduced as slabstock foam.

Polyurethane composites can also be produced in sandwich mode. Themethod may be configured either as a depot method or a shell-buildingmethod. Both the depot method and the shell-building method are knownper se. In the depot method (filling mode), two half-shells (for exampleouter layers made from polymers) are prefabricated and inserted into amould, and the cavity between the shells is filled by foaming with thePUR foam. In shell-building mode, a core of PUR foam is placed in amould and then encased with a suitable shell material, for example withone of the thermoplastics mentioned. In the production of sandwichcomposites, preference is given to shell-building mode.

In a preferred embodiment of the invention, the composite components areproduced by a process in which

-   -   (i) in a first process step the melt of the thermoplastic        composition is injected into a first mould cavity and then        cooled,    -   (ii) in a second process step the thermoplastic component is        transferred into a larger cavity and a defined gap is produced        thereby,    -   (iii) in the third process step the gap which thus results        between the thermoplastic component and the mould surface of the        enlarged cavity is injected with a reactive polyurethane raw        material mixture comprising    -   at least one polyisocyanate component,    -   at least one polyfunctional H-active compound, and    -   optionally at least one polyurethane additive and/or processing        aid, the polyurethane raw material mixture polymerizing fully in        direct contact with the surface of the thermoplastic carrier to        give a compact polyurethane layer or to give a polyurethane foam        layer, and    -   (iv) in the fourth process step the composite component is        demoulded from the mould cavity.

In a further preferred embodiment of the invention, process steps (i) to(iv) follow one another in immediate succession in the compositecomponent production.

If required, the larger cavity is treated with a separating agent priorto process step (iii).

The immediate succession of the process steps prevents the workpiecefrom cooling down to room temperature during the process. This achievesa reduction in the production times and a higher energy efficiency ofthe overall process.

Process steps (ii) and (iii) can be repeated at least once withvariation of the polyurethane system, in which case one or morepolyurethane layers are applied to one or both sides of the carrier, soas to result in a composite component composed of thermoplastic carrierand at least two identical or different PU components which mayoptionally also have a more than two-layer structure.

Before the demoulding of the workpiece in steps (ii) and (iv), theworkpiece is cooled down until it is dimensionally stable.

To produce the gap in process step (ii), it is possible to open theinjection mould and subsequently to exchange half of the injection mouldcavity for a new half with greater cavity dimensions, or to move thecomponent from the first mould cavity to a second cavity which is largerin terms of its cavity dimensions or to a second mould, or to open upthe first cavity to create a gap.

The movement of the substrate in process step (ii) can be effected byknown processes, as employed, for example, in multicolour injectionmoulding. Typical methods are firstly movement with a turntable, aturning plate, a sliding cavity or an index plate, or comparable methodsin which the substrate remains on a core. If the substrate for movementremains on the core, this has the advantage that the position is definedaccurately even after the movement. Secondly, the prior art disclosesmethods for moving a substrate in which the substrate is removed from acavity, for example with the aid of a handling system, and placed intoanother cavity. Movement with removal of the substrate offers greaterfreedom of configuration in the coating operation, for example in thegeneration of an edge fold or masked regions.

In a preferred embodiment, in the first process step, a thermoplasticpolymer composition which at room temperature has high toughness in thenotched impact test to ISO 180-1A, characterized by a notched impactresistance value of greater than 25 kJ/m², and additionally achieves theUL 94-V V-1 or V-0 flame retardancy class with sample thickness 1 mm, isused.

The reactive polyurethane raw material mixtures used in the productionof the inventive composite components preferably have an index of >80 to<125, further preferably >90 to <120, and more preferably von 100 to110.

The index is defined as the percentage ratio of the amount of isocyanateactually used to the calculated stoichiometric amount in the case ofcomplete reaction with the H-active polyfunctional component, i.e.index=(amount of isocyanate used/calculated stoichiometric amount ofisocyanate)*100.

In an alternative embodiment, rather than the reactive polyurethane rawmaterial mixture, it is also possible to use a thermoplasticpolyurethane.

In a further preferred embodiment, the surface of the injection mould incontact with the thermoplastic polymer composition is heated in processstep (iii) to a temperature in the range of 50 to 100° C., preferably 55to 95° C., and more preferably 60 to 90° C.

In a further preferred embodiment, the surface of the injection mould incontact with the reactive polyurethane mixture is heated in process step(iii) to a temperature in the range of 50 to 160° C., preferably 50 to120° C., further preferably 60 to 110° C., and more preferably 60 to 90°C.

In a further preferred embodiment, the surface of the injection mould incontact with the thermoplastic polymer composition is heated in processstep (iii) to a temperature in the range of 50 to 100° C., preferably 55to 95° C., and more preferably 60 to 90° C., and the surface of theinjection mould in contact with the reactive polyurethane mixture to atemperature in the range of 50 to 160° C., preferably 50 to 120° C.,further preferably 60 to 110° C., and more preferably 60 to 90° C.

If a foamed polyurethane system with a decorative layer is involved, inan alternative embodiment, the surface of the foaming mould in contactwith the thermoplastic polymer composition or with the decorative skincan be heated to a temperature in the range of 20 to 80° C., preferably30 to 60° C.

The inventive composite components are particularly suitable as aninterior or exterior component of a rail vehicle, aircraft or motorvehicle, and for electrical/electronic components and IT components.

The composite adhesion between the carrier composed of polycarbonatecomposition and the polyurethane coating in the inventive compositecomponents, in a preferred embodiment, is at least 1 N/mm, measured onstrip samples taken from the component having a width of 20 mm in afloating roller test to DIN EN 1464 with a traversing speed of 100mm/min.

The polymer compositions used in the process according to the inventioncomprise:

Component A

Aromatic polycarbonates and/or aromatic polyester carbonates ofcomponent A which are suitable in accordance with the invention areknown from the literature or preparable by processes known from theliterature (for preparation of aromatic polycarbonates see, for example,Schnell, “Chemistry and Physics of Polycarbonates”, IntersciencePublishers, 1964, and also DE-B 1 495 626, DE-A 2 232 877, DE-A 2 703376, DE-A 2 714 544, DE-A 3 000 610, DE-A 3 832 396; for preparation ofaromatic polyester carbonates, for example DE-A 3 077 934).

Aromatic polycarbonates and polyester carbonates are prepared, forexample, by reacting diphenols with carbonic halides, preferablyphosgene, and/or with aromatic dicarbonyl dihalides, preferablybenzenedicarbonyl dihalides, by the interfacial process, optionallyusing chain terminators, for example monophenols, and optionally usingtrifunctional or more than trifunctional branching agents, for exampletriphenols or tetraphenols. Preparation is likewise possible via a meltpolymerization process through reaction of diphenols with, for example,diphenyl carbonate.

Diphenols for preparation of the aromatic polycarbonates and/or aromaticpolyester carbonates are preferably those of the formula (I)

where

A is a single bond, C₁ to C₅-alkylene, C₂ to C₅-alkylidene, C₅ toC₆-cycloalkylidene, —O—, —SO—, —CO—, —S—, —SO₂—, C₆ to C₁₂-arylene, ontowhich may be fused further aromatic rings optionally containingheteroatoms,

or a radical of the formula (II) or (III)

-   B in each case is C₁ to C₁₂-alkyl, preferably methyl, halogen,    preferably chlorine and/or bromine,-   x in each case is independently 0, 1 or 2,-   p is 1 or 0, and-   R⁵ and R⁶ can be chosen individually for each X¹ and are each    independently hydrogen or C₁ to C₆-alkyl, preferably hydrogen,    methyl or ethyl,-   X¹ is carbon and-   m is an integer from 4 to 7, preferably 4 or 5, with the proviso    that R⁵ and R⁶ on at least one X¹ atom are simultaneously alkyl.

Preferred diphenols are hydroquinone, resorcinol, dihydroxydiphenols,bis(hydroxyphenyl)-C₁-C₅-alkanes, bis(hydroxyphenyl)-C₅-C₆-cycloalkanes,bis(hydroxyphenyl) ethers, bis(hydroxyphenyl) sulphoxides,bis(hydroxyphenyl) ketones, bis(hydroxyphenyl) sulphones andα,α-bis(hydroxyphenyl)diisopropylbenzenes, and the ring-brominatedand/or ring-chlorinated derivatives thereof.

Particularly preferred diphenols are 4,4′-dihydroxydiphenyl, bisphenolA, 2,4-bis(4-hydroxyphenyl)-2-methylbutane,1,1-bis(4-hydroxyphenyl)cyclohexane,1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,4,4′-dihydroxydiphenyl sulphide, 4,4′-dihydroxydiphenyl sulphone and thedi- and tetrabrominated or -chlorinated derivatives thereof, for example2,2-bis(3-chloro-4-hydroxyphenyl)propane,2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane or2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane.2,2-Bis(4-hydroxyphenyl)propane (bisphenol A) is especially preferred.

It is possible to use the diphenols individually or in the form of anydesired mixtures. The diphenols are known from the literature orobtainable by processes known from the literature.

Examples of chain terminators suitable for the preparation of thethermoplastic aromatic polycarbonates include phenol, p-chlorophenol,p-tert-butylphenol or 2,4,6-tribromophenol, but also long-chainalkylphenols such as 4-[2-(2,4,4-trimethylpentyl)]phenol,4-(1,3-tetramethylbutyl)phenol according to DE-A 2 842 005 ormonoalkylphenols or dialkylphenols having a total of 8 to 20 carbonatoms in the alkyl substituents, such as 3,5-di-tert-butylphenol,p-isooctylphenol, p-tert-octylphenol, p-dodecylphenol and2-(3,5-dimethylheptyl)phenol and 4-(3,5-dimethylheptyl)phenol. Theamount of chain terminators to be used is generally between 0.5 mol %and 10 mol %, based on the molar sum of the diphenols used in each case.

The thermoplastic aromatic polycarbonates may be branched in a knownmanner, preferably through the incorporation of 0.05 to 2.0 mol %, basedon the sum total of the diphenols used, of trifunctional or more thantrifunctional compounds, for example those having three or more phenolicgroups.

Both homopolycarbonates and copolycarbonates are suitable. Forpreparation of inventive copolycarbonates of component A, it is alsopossible to use 1% to 25% by weight, preferably 2.5% to 25% by weight,based on the total amount of diphenols to be used, ofpolydiorganosiloxanes having hydroxyaryloxy end groups. These are known(U.S. Pat. No. 3,419,634) and are preparable by processes known from theliterature. The preparation of polydiorganosiloxane-containingcopolycarbonates is described in DE-A 3 334 782.

Preferred polycarbonates are, as well as the bisphenol Ahomopolycarbonates, the copolycarbonates of bisphenol A with up to 15mol %, based on the molar sums of diphenols, of other diphenolsspecified as preferred or particularly preferred, especially2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane.

Aromatic dicarbonyl dihalides for preparation of aromatic polyestercarbonates are preferably the diacid dichlorides of isophthalic acid,terephthalic acid, diphenyl ether 4,4′-dicarboxylic acid andnaphthalene-2,6-dicarboxylic acid.

Particular preference is given to mixtures of the diacid dichlorides ofisophthalic acid and terephthalic acid in a ratio between 1:20 and 20:1.

In the preparation of polyester carbonates, a carbonic halide,preferably phosgene, is also used as a bifunctional acid derivative.

Useful chain terminators for the preparation of the aromatic polyestercarbonates include, apart from the monophenols already mentioned, thechlorocarbonic esters thereof and the acid chlorides of aromaticmonocarboxylic acids, which may optionally be substituted by C₁ toC₂₂-alkyl groups or by halogen atoms, and aliphatic C₂ toC₂₂-monocarbonyl chlorides.

The amount of chain terminators in each case is 0.1 to 10 mol %, basedon moles of diphenol in the case of the phenolic chain terminators andon moles of dicarbonyl dichloride in the case of monocarbonyl chloridechain terminators.

The aromatic polyester carbonates may also contain incorporated aromatichydroxycarboxylic acids.

The aromatic polyester carbonates may be either linear or branched in aknown manner (see DE-A 2 940 024 and DE-A 3 007 934).

Branching agents used may, for example, be tri- or multifunctionalcarbonyl chlorides, such as trimesyl trichloride, cyanuric trichloride,3,3′,4,4′-benzophenonetetracarbonyl tetrachloride,1,4,5,8-naphthalenetetracarbonyl tetrachloride or pyromellitictetrachloride, in amounts of 0.01 to 1.0 mol % (based on dicarbonyldichlorides used), or tri- or multifunctional phenols, such asphloroglucinol, 4,6-dimethyl-2,4,6-tri(4-hydroxyphenyl)hept-2-ene,4,6-dimethyl-2,4-6-tri(4-hydroxyphenyl)heptane,1,3,5-tri(4-hydroxyphenyl)benzene, 1,1,1-tri(4-hydroxyphenyl)ethane,tri(4-hydroxyphenyl)phenylmethane, 2,2-bis[4,4-bis(4-hydroxyphenyl)cyclohexyl]propane,2,4-bis(4-hydroxyphenylisopropyl)phenol, tetra(4-hydroxyphenyl)methane,2,6-bis(2-hydroxy-5-methylbenzyl)-4-methy 1phenol,2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl)propane,tetra(4-[4-hydroxyphenylisopropyl]phenoxy)methane, 1,4-bis[4,4′-dihydroxytriphenyl)methyl]benzene, in amounts of 0.01 to 1.0 mol%, based on diphenols used. Phenolic branching agents may be initiallycharged together with the diphenols; acid chloride branching agents maybe introduced together with the acid dichlorides.

The proportion of carbonate structural units in the thermoplasticaromatic polyester carbonates may vary as desired. Preferably, theproportion of carbonate groups is up to 100 mol %, especially up to 80mol %, more preferably up to 50 mol %, based on the sum total of estergroups and carbonate groups. Both the ester fraction and the carbonatefraction of the aromatic polyester carbonates may be present in the formof blocks or in random distribution in the polycondensate.

The relative solution viscosity (η_(rel)) of aromatic polycarbonates andpolyester carbonates is preferably in the range of 1.18 to 1.4, morepreferably in the range of 1.20 to 1.32 (measured in solutions of 0.5 gof polycarbonate or polyester carbonate in 100 ml of methylene chlorideat 25° C.). The weight-average molecular weight Mw of aromaticpolycarbonates and polyester carbonates is preferably in the range from15 000 to 35 000, further preferably in the range from 20 000 to 33 000,more preferably 23 000 to 30 000, determined by GPC (gel permeationchromatography in methylene chloride with polycarbonate as standard).

Component B

Component B comprises polybutadiene-based graft polymers or mixtures ofpolybutadiene-based graft polymers with butadiene-free vinyl(co)polymers, the butadiene content of component B being at least 25.0%by weight.

Polybutadiene-based graft polymers used in component B comprise

-   -   B.1 5% to 95%, preferably 15% to 92% and especially 25% to 60%        by weight, based on the graft polymer, of at least one vinyl        monomer on    -   B.2 95% to 5%, preferably 85% to 8% and especially 75% to 40% by        weight, based on the graft polymer, of one or more        polybutadiene-based graft bases.

The graft base B.2 generally has a median particle size (d₅₀) of 0.05 to10.00 μm, preferably 0.1 to 5.0 μm, more preferably 0.2 to 1.0 μm, andmost preferably 0.2 to 0.5 μm.

The mean particle size d₅₀ is the diameter above which and below which50% by weight of the particles lie. It can be determined by means ofultracentrifuge measurement (W. Scholtan, H. Lange, Kolloid, Z. and Z.Polymere 250 (1972), 782-1796).

Monomers B.1 are preferably mixtures of

-   B.1.1 50% to 99%, preferably 65% to 85% and especially 75% to 80% by    weight, based on B.1, of vinylaromatics and/or ring-substituted    vinylaromatics (such as styrene, α-methylstyrene, p-methylstyrene,    p-chlorostyrene) and/or (C₁-C₈)-alkyl methacrylates such as methyl    methacrylate, ethyl methacrylate), and-   B.1.2 1% to 50%, preferably 15% to 35% and especially 20% to 25% by    weight, based on B.1, of vinyl cyanides (unsaturated nitriles such    as acrylonitrile and methacrylonitrile) and/or (C₁-C₈)-alkyl    (meth)acrylates such as methyl methacrylate, n-butyl acrylate,    t-butyl acrylate, and/or derivatives (such as anhydrides and imides)    of unsaturated carboxylic acids, for example maleic anhydride and    N-phenylmaleimide.

Preferred monomers B.1.1 are selected from at least one of the monomersstyrene, a-methylstyrene and methyl methacrylate; preferred monomersB.1.2 are selected from at least one of the monomers acrylonitrile,maleic anhydride and methyl methacrylate. Particularly preferredmonomers are B.1.1 styrene and B.1.2 acrylonitrile.

Graft bases B.2 suitable for the graft polymers in component B are purepolybutadiene rubbers or mixtures of polybutadiene rubbers or copolymersof polybutadiene rubbers or mixtures thereof with furthercopolymerizable monomers (for example according to B.1.1 and B.1.2),with the proviso that the glass transition temperature of component B.2is below <10° C., preferably <0° C., more preferably <−20° C.

The glass transition temperature was determined by means of differentialthermoanalysis (DSC) according to the standard DIN EN 61006 at a heatingrate 10 K/min with T_(g) defined as the midpoint temperature (tangentmethod).

A particularly preferred graft base B.2 is pure polybutadiene rubber.

Particularly preferred polymers in component B are, for example, ABS orMBS polymers as described, for example, in DE-A 2 035 390 (=U.S. Pat.No. 3,644,574) or in DE-A 2 248 242 (=GB-A 1 409 275) or in Ullmanns,Enzyklopädie der Technischen Chemie [Encyclopaedia of IndustrialChemistry], vol. 19 (1980), p. 280 ff.

The graft copolymers in component B are prepared by free-radicalpolymerization, for example by emulsion, suspension, solution or bulkpolymerization, especially by emulsion polymerization.

In the case of graft polymers in component B which have been prepared inan emulsion polymerization process, the content of graft base B.2 ispreferably 20% to 95% by weight, more preferably 40% to 85% by weight,especially 50% to 75% by weight, based in each case on the graftpolymer.

The gel content of the graft base B.2 is at least 30% by weight,preferably at least 40% by weight, especially at least 60% by weight,based in each case on B.2 and measured as the insoluble component intoluene.

Since the grafting reaction, as is well known, does not necessarilygraft the graft monomers completely onto the graft base, according tothe invention, graft polymers in component B are also understood to meanthose products which are obtained by (co)polymerization of the graftmonomers B.1 in the presence of the graft base B.2 and are also obtainedin the workup. These products may accordingly also contain free(co)polymer of the graft monomers B.1 not chemically bonded to thepolybutadiene.

The gel content of the graft base B.2 or of the graft polymers incomponent B is determined at 25° C. in a suitable solvent as thecomponent insoluble in these solvents (M. Hoffmann, H. Krömer, R. Kuhn,Polymeranalytik I and II [Polymer Analysis I and II], GeorgThieme-Verlag, Stuttgart 1977).

The butadiene-free vinyl (co)polymers in component B are preferablybutadiene-free homo- and/or copolymers B.1 of at least one monomer fromthe group of the vinylaromatics, vinyl cyanides (unsaturated nitriles),(C₁ to C₈)-alkyl (meth)acrylates, unsaturated carboxylic acids andderivatives (such as anhydrides and imides) of unsaturated carboxylicacids.

These (co)polymers B.1 are resinous, thermoplastic and butadiene-free.More preferably, the copolymer is formed from B.1.1 styrene and B.1.2acrylonitrile.

(Co)polymers B.1 of this kind are known and can be prepared byfree-radical polymerization, especially by emulsion, suspension,solution or bulk polymerization. The (co)polymers preferably haveaverage molecular weights M_(w) (weight-average, determined by GPC)between 15 000 g/mol and 250 000 g/mol, preferably in the range of 80000 to 150 000 g/mol.

Component C

Phosphorus-containing flame retardants C in the context of the inventionare selected from the groups of the mono- and oligomeric phosphoric andphosphonic esters, phosphonate amines and phosphazenes, and it is alsopossible to use mixtures of a plurality of components selected from oneof these groups or various groups as flame retardants.

Mono- and oligomeric phosphoric and phosphonic esters in the context ofthe invention are phosphorus compounds of the general formula (V)

in which

R1, R2, R3 and R4 are each independently optionally halogenated C1 toC8-alkyl, in each case optionally alkyl-substituted, preferably C1 toC4-alkyl-substituted, and/or halogen-substituted, preferably chlorine-,bromine-substituted, C5 to C6-cycloalkyl, C6 to C20-aryl or C7 toC12-aralkyl,

n is independently 0 or 1

q is 0 to 30 and

X is a polycyclic aromatic radical having 12 to 30 carbon atoms, or alinear or branched aliphatic radical having 2 to 30 carbon atoms, whichmay be OH-substituted and may contain up to eight ether bonds.

Preferably, R1, R2, R3 and R4 are each independently C1 to C4-alkyl,phenyl, naphthyl or phenyl-C1-C4-alkyl. The aromatic R1, R2, R3 and R4groups may in turn be substituted by halogen and/or alkyl groups,preferably chlorine, bromine and/or C1 to C4-alkyl. Particularlypreferred aryl radicals are cresyl, phenyl, xylenyl, propylphenyl orbutylphenyl, and the corresponding brominated and chlorinatedderivatives thereof.

X in the formula (V) is preferably a polycyclic aromatic radical having12 to 30 carbon atoms. The latter preferably derives from diphenols ofthe formula (I).

n in the formula (V) may independently be 0 or 1; n is preferably 1.

q represents integer values from 0 to 30, preferably 0 to 20, morepreferably 0 to 10, and in the case of mixtures represents averagevalues of 0.8 to 5.0, preferably 1.0 to 3.0, further preferably 1.05 to2.00, and more preferably von 1.08 to 1.60.

X is more preferably

or chlorinated or brominated derivatives thereof; more particularly, Xderives from bisphenol A or diphenylphenol. More preferably, X derivesfrom bisphenol A.

Phosphorus compounds of the formula (V) are especially tributylphosphate, triphenyl phosphate, tricresyl phosphate, diphenyl cresylphosphate, diphenyl octyl phosphate, diphenyl 2-ethylcresyl phosphate,tri(isopropylphenyl) phosphate, and bisphenol A-bridged oligophosphate.The use of oligomeric phosphoric esters of the formula (V) which derivefrom bisphenol A is especially preferred.

Most preferred as component C is bisphenol A-based oligophosphate of theformula (Va).

The phosphorus compounds of component C are known (cf., for example,EP-A 0 363 608, EP-A 0 640 655) or can be prepared in an analogousmanner by known methods (e.g. Ullmanns Enzyklopädie der technischenChemie, vol. 18, p. 301 ff. 1979; Houben-Weyl, Methoden der organischenChemie [Methods of Organic Chemistry], vol. 12/1, p. 43; Beilstein vol.6, p. 177).

As component C according to the invention, it is also possible to usemixtures of phosphates having different chemical structure and/or havingthe same chemical structure and different molecular weight.

Preference is given to using mixtures having the same structure anddifferent chain length, where the q value stated is the average q value.The average q value is determined by determining the composition of thephosphorus compound (molecular weight distribution) by means ofhigh-pressure liquid chromatography (HPLC) at 40° C. in a mixture ofacetonitrile and water (50:50) and calculating the average values for qtherefrom.

In addition, it is possible to use phosphonate amines and phosphazenesas described in WO 00/00541 and WO 01/18105 as flame retardants.

The flame retardants can be used alone or in any desired mixture withone another or in a mixture with other flame retardants.

If the inventive compositions have been rendered flame-retardant, ananti-dripping agent, preferably polytetrafluoroethylene (PTFE), ispreferably additionally present.

Component D

The composition may comprise conventional polymer additives as componentD. Possible conventional polymer additives for component D includeadditives such as flame retardant synergists, anti-dripping agents (forexample compounds from the substance classes of the fluorinatedpolyolefins, the silicones and aramid fibres), internal and externallubricants and demoulding agents (for example pentaerythrityltetrastearate, stearyl stearate, montan wax or polyethylene wax),flowability aids, antistats (for example block copolymers of ethyleneoxide and propylene oxide, other polyethers or polyhydroxy ethers,polyether amides, polyester amides or sulphonic salts), conductivityadditives (for example conductive black or carbon nanotubes),stabilizers (for example UV/light stabilizers, thermal stabilizers,antioxidants, hydrolysis stabilizers), antibacterial additives (forexample silver or silver salts), scratch resistance-improving additives(for example silicone oils or hard fillers such as (hollow) ceramicbeads), IR absorbents, optical brighteners, fluorescent additives, andalso dyes and pigments (for example carbon black, titanium dioxide oriron oxide), impact modifiers not covered by the definition of B, andBrønsted-acidic compounds as base scavengers, or else mixtures of aplurality of the additives mentioned.

More particularly, anti-dripping agents used are polytetrafluoroethylene(PTFE) or PTFE-containing compositions, for example masterbatches ofPTFE with styrene- or methyl methacrylate-containing polymers orcopolymers, as a powder or as a coagulated mixture, for example withcomponent B.

The fluorinated polyolefins used as anti-dripping agents have a highmolecular weight and have glass transition temperatures exceeding −30°C., generally exceeding 100° C., fluorine contents preferably of 65% to76% and especially of 70% to 76% by weight, median particle diametersd₅₀ of 0.05 to 1000 μm, preferably 0.08 to 20 μm. In general, thefluorinated polyolefins have a density of 1.2 to 2.3 g/cm³. Preferredfluorinated polyolefins are polytetrafluoroethylene, polyvinylidenefluoride, tetrafluoroethylene/hexafluoropropylene andethylene/tetrafluoroethylene copolymers. The fluorinated polyolefins areknown (cf. “Vinyl and Related Polymers” by Schildknecht, John Wiley &Sons, Inc., New York, 1962, pages 484-494; “Fluoropolymers” by Wall,Wiley-Interscience, John Wiley & Sons, Inc., New York, volume 13, 1970,page 623-654; “Modern Plastics Encyclopedia”, 1970-1971, volume 47, No.10 A, October 1970, McGraw-Hill, Inc., New York, pages 134 and 774;“Modern Plastics Encyclopedia”, 1975-1976, October 1975, volume 52, No.10 A, McGraw-Hill, Inc., New York, pages 27, 28 and 472 and U.S. Pat.Nos. 3,671,487, 3,723,373 and 3,838,092).

Suitable fluorinated polyolefins D usable in powder form aretetrafluoroethylene polymers having median particle diameters of 100 to1000 μm and densities of 2.0 g/cm³ to 2.3 g/cm³. Suitabletetrafluoroethylene polymer powders are commercial products and aresupplied, for example, by DuPont under the Teflon® trade name.

More preferably, the inventive compositions comprise at least onedemoulding agent, preferably pentaerythrityl tetrastearate inproportions by weight of 0.1% to 1.0% by weight based on the sum totalof components A to D, and at least one stabilizer, preferably a phenolicantioxidant, more preferably2,6-di-tert-butyl-4-(octadecanoxycarbonylethyl)phenol in proportions byweight of 0.01% to 1.0% by weight, based on the sum total of componentsA to D.

Further preference is given to a stabilizer combination of at least twostabilizers, the second stabilizer comprising a Brønsted-acidic compoundin proportions by weight of 0.01% to 1.0% based on the sum total ofcomponents A to D. Preferably, the second stabilizer is phosphoric acid,aqueous phosphoric acid solution or a free-flowing blend of phosphoricacid or an aqueous phosphoric acid solution with a finely dividedhydrophilic silica gel in proportions by weight of 0.01% to 1.0%, basedon the sum total of components A to D.

Another further preferred additive is citric acid in proportions byweight of 0.05% to 1.0%, based on the sum total of components A to D.

In a preferred embodiment, the compositions do not comprise, ascomponent D, any fillers and reinforcers, for example talc, glass fibresor carbon fibres (optionally including ground fibres), (hollow) glass orceramic beads, mica, kaolin, CaCO₃ and glass flakes.

Polyurethane Layer

The polyurethane layer used is preferably a polyurethane foam or acompact polyurethane layer.

The polyurethanes used in accordance with the invention are obtained byreacting polyisocyanates with H-active polyfunctional compounds,preferably polyols.

In the context of this invention, the term “polyurethane” is alsounderstood to mean polyurethaneureas in which the H-activepolyfunctional compounds used are those compounds having N—Hfunctionality, optionally in a blend with polyols.

Suitable polyisocyanates are the aromatic, araliphatic, aliphatic orcycloaliphatic polyisocyanates which are known per se to those skilledin the art and have NCO functionality of preferably 2, which may alsohave iminooxadiazinedione, isocyanurate, uretdione, urethane,allophanate, biuret, urea, oxadiazinetrione, oxazolidinone, acylureaand/or carbodiimide structures. These can be used individually or in anydesired mixtures with one another.

The aforementioned polyisocyanates are based on di- or triisocyanateswhich are known per se to those skilled in the art and havealiphatically, cycloaliphatically, araliphatically and/or aromaticallybonded isocyanate groups, it being unimportant whether these have beenprepared using phosgene or by phosgene-free methods. Examples of suchdi- or triisocyanates are 1,4-diisocyanatobutane,1,5-diisocyanatopentane, 1,6-diisocyanatohexane (HDI),2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanato-2,2-dimethylpentane,2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane,1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1,3- and1,4-bis(isocyanatomethyl)-cyclohexane,1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophoronediisocyanate, IPDI), 4,4′-diisocyanatodicyclohexylmethane (Desmodur® W,Bayer AG, Leverkusen, DE), 4-isocyanatomethyl-1,8-octane diisocyanate(triisocyanatononane, TIN), ω,ω′-diisocyanato-1,3-dimethylcyclohexane(H₆XDI), 1-isocyanato-1-methyl-3-isocyanatomethylcyclohexane,1-isocyanato-1-methyl-4-isocyanatomethylcyclohexane,bis(isocyanatomethyl)-norbornane, naphthalene 1,5-diisocyanate, 1,3- and1, 4-bis(2-isocyanatoprop-2-yl)benzene (TMXDI), 2,4- and2,6-diisocyanatotoluene (TDI), especially the 2,4 and the 2,6 isomer,and technical mixtures of the two isomers, 2,4′- and4,4′-diisocyanatodiphenylmethane (MDI), polymeric MDI (pMDI),1,5-diisocyanatonaphthalene, 1,3-bis(isocyanatomethyl)benzene (XDI) andany desired mixtures of the compounds mentioned.

The polyisocyanates preferably have an average NCO functionality of 2.0to 5.0, preferably of 2.2 to 4.5, more preferably of 2.2 to 2.7, and acontent of isocyanate groups of 5.0% to 37.0% by weight, preferably of14.0% to 34.0% by weight.

In a preferred embodiment, polyisocyanates or polyisocyanate mixtures ofthe above-specified type having exclusively aliphatically and/orcycloaliphatically bonded isocyanate groups are used.

Most preferably, the polyisocyanates of the above-specified type arebased on hexamethylene diisocyanate, isophorone diisocyanate, theisomeric bis(4,4′-isocyanatocyclohexyl)methanes and mixtures thereof.

Among the modified polyisocyanates of relatively high molecular weight,the prepolymers known from polyurethane chemistry which have terminalisocyanate groups and are of the molecular weight range of 400 to 15000, preferably 600 to 12 000, are of particular interest. Thesecompounds are prepared in a manner known per se by reaction of excessamounts of simple polyisocyanates of the type specified by way ofexample with organic compounds having at least two groups reactivetoward isocyanate groups, especially organic polyhydroxyl compounds.Suitable polyhydroxyl compounds of this kind are simple polyhydricalcohols of the molecular weight range of 62 to 599, preferably 62 to200, for example ethylene glycol, trimethylolpropane, propane-1,2-diolor butane-1,4-diol or butane-2,3-diol, but especially high molecularweight polyether polyols and/or polyester polyols of the kind known perse from polyurethane chemistry, having molecular weights of 600 to 12000, preferably 800 to 4000, and having at least two, generally 2 to 8,but preferably 2 to 6, primary and/or secondary hydroxyl groups. It isof course also possible to use those NCO prepolymers which, for example,have been obtained from lower molecular weight polyisocyanates of thetype specified by way of example and less preferred compounds havinggroups reactive toward isocyanate groups, for example polythioetherpolyols, polyacetals having hydroxyl groups, polyhydroxypolycarbonates,polyester amides having hydroxyl groups or hydroxyl-containingcopolymers of olefinically unsaturated compounds.

Compounds which have groups reactive toward isocyanate groups,especially hydroxyl groups, and are suitable for preparation of the NCOprepolymers are, for example, the compounds disclosed in U.S. Pat. No.4,218,543. In the preparation of the NCO prepolymers, these compoundshaving groups reactive toward isocyanate groups are reacted with simplepolyisocyanates of the type specified above by way of example whilemaintaining an NCO excess. The NCO prepolymers generally have an NCOcontent of 10% to 26% and preferably 15% to 26% by weight. It is alreadyclear from this that, in the context of the present invention, “NCOprepolymers” and “prepolymers having terminal isocyanate groups” areunderstood to mean both the reaction products and the mixtures withexcess amounts of unconverted starting polyisocyanates, which are oftenalso referred to as “semiprepolymers”.

Useful aliphatic diols having an OH number of >500 mg KOH/g includes thechain extenders customarily used in polyurethane chemistry, such asethylene glycol, diethylene glycol, propylene glycol, dipropyleneglycol, butane-1,4-diol, propane-1,3-diol. Preference is given to diolssuch as 2-butane-1,4-diol, butane-1,3-diol, butane-2,3-diol and/or2-methylpropane-1,3-diol. It will be appreciated that it is alsopossible to use the aliphatic diols in a mixture with one another.

Suitable H-active components are polyols having an average OH number of5 to 600 mg KOH/g and an average functionality of 2 to 6. Polyolssuitable in accordance with the invention are, for example, polyhydroxypolyethers obtainable by alkoxylation of suitable starter molecules suchas ethylene glycol, diethylene glycol, 1,4-dihydroxybutane,1,6-dihydroxyhexane, dimethylolpropane, glycerol, pentaerythritol,sorbitol or sucrose. Starters used may likewise be ammonia or aminessuch as ethylenediamine, hexamethylenediamine, 2,4-diaminotoluene,aniline or amino alcohols or phenols such as bisphenol A. Thealkoxylation is effected using propylene oxide and/or ethylene oxide inany desired sequence or as a mixture.

As well as polyols, it is additionally possible for at least onecrosslinker and/or chain extender to be present, selected from the groupcomprising the amines and amino alcohols, for example ethanolamine,diethanolamine, diisopropanolamine, ethylenediamine, triethanolamine,isophoronediamine, N,N′-dimethyl(diethyl)ethylenediamine,2-amino-2-methyl(or ethyl)-1-propanol, 2-amino-1-butanol,3-amino-1,2-propanediol, 2-amino-2-methyl(ethyl)-1,3-propanediol, andalcohols, for example ethylene glycol, diethylene glycol,1,4-dihydroxybutane, 1,6-dihydroxyhexane, dimethylolpropane, glyceroland pentaerythritol, and also sorbitol and sucrose, or mixtures of thesecompounds.

Also suitable are polyester polyols as obtainable in a manner known perse by reaction of low molecular weight alcohols with polybasiccarboxylic acids such as adipic acid, phthalic acid, hexahydrophthalicacid, tetrahydrophthalic acid or the anhydrides of these acids, providedthat the viscosity of the H-active component does not become too great.A preferred polyol having ester groups is castor oil. Also additionallysuitable are formulations comprising castor oil, as obtainable bydissolution of resins, for example of aldehyde-ketone resins, andmodifications of castor oil and polyols based on other natural oils.

Likewise suitable are those polyhydroxy polyethers of relatively highmolecular weight in which high molecular weight polyadducts orpolycondensates or polymers are present in finely dispersed, dissolvedor grafted form. Modified polyhydroxyl compounds of this kind areobtainable in a manner known per se, for example, when polyadditionreactions (e.g. reactions between polyisocyanates and amino-functionalcompounds) or polycondensation reactions (for example betweenformaldehyde and phenols and/or amines) are allowed to proceed in situin the compounds having hydroxyl groups. Alternatively, it is alsopossible to mix a finished aqueous polymer dispersion with apolyhydroxyl compound and then to remove the water from the mixture.

Polyhydroxyl compounds modified by vinyl polymers, as obtained, forexample, by polymerization of styrene and acrylonitrile in the presenceof polyethers or polycarbonate polyols, are also suitable for thepreparation of polyurethanes. When polyether polyols which have beenmodified according to DE-A 2 442 101, DE-A 2 844 922 and DE-A 2 646 141by graft polymerization with vinyl phosphonates and optionally(meth)acrylonitrile, (meth)acrylamide or OH-functional (meth)acrylicesters are used, polymers of exceptional flame retardancy are obtained.

Representatives of the compounds to be used as H-active compoundsmentioned are described, for example, in High Polymers, Vol. XVI,“Polyurethanes Chemistry and Technology”, Saunders-Frisch (ed.)Interscience Publishers, New York, London, vol. 1, p. 32-42, 44, 54 andvol. II, 1984, p. 5-6 and p. 198-199.

It is also possible to use mixtures of the compounds enumerated.

The limitation of the average OH number and the average functionality ofthe H-active component arises particularly from the increasingembrittlement of the resulting polyurethane. In principle, however, theperson skilled in the art is aware of the ways of influencing thephysical polymer properties of the polyurethane, such that NCOcomponent, aliphatic diol and polyol can be matched to one another in afavourable manner.

The polyurethane layer (b) may be in foamed or solid form, for exampleas a lacquer or coating.

It can be produced using any of the assistants and additives known perse, for example separating agents, blowing agents, fillers, catalystsand flame retardants.

Assistants and additives for optional use are:

a) Water and/or volatile inorganic or organic substances as blowingagents

Useful organic blowing agents include, for example, acetone, ethylacetate, halogen-substituted alkanes such as methylene chloride,chloroform, ethylidene chloride, vinylidene chloride,monofluorotrichloromethane, chlorodifluoromethane,dichlorodifluoromethane, and also butane, hexane, heptane or diethylether, and useful inorganic blowing agents include air, CO₂ or N₂O. Ablowing effect can also be achieved through addition of compounds thatdecompose at temperatures exceeding room temperature with elimination ofgases, for example of nitrogen, examples being azo compounds such asazodicarbonamide and azoisobutyronitrile.

b) Catalysts

The catalysts are, for example, tertiary amines (such as triethylamine,tributylamine, N-methylmorpholine, N-ethylmorpholine,N,N,N′,N′-tetramethylethylenediamine, pentamethyldiethylenetriamine andhigher homologues, 1,4-diazabicyclo [2.2.2]octane,N-methyl-N′-dimethylaminoethylpiperazine,bis(dimethylaminoalkyl)piperazines, N,N-dimethylbenzylamine,N,N-dimethylcyclohexylamine, N,N-diethylbenzylamine,bis(N,N-diethylaminoethyl) adipate,N,N,N′,N′-tetramethyl-1,3-butanediamine,N,N-dimethyl-β-phenylethylamine, 1,2-dimethyl-imidazole,2-methylimidazole), monocyclic and bicyclic amides,bis(dialkylamino)alkyl ethers, tertiary amines having amide groups(preferably formamide groups), Mannich bases formed from secondaryamines (such as dimethylamine) and aldehydes (preferably formaldehyde orketones such as acetone, methyl ethyl ketone or cyclohexanone) andphenols (such as phenol, nonylphenol or bisphenol), tertiary amineshaving hydrogen atoms active toward isocyanate groups (e.g.triethanolamine, triisopropanolamine, N-methyldiethanolamine,N-ethyldiethanolamine, N,N-dimethylethanolamine), and the reactionproducts thereof with alkylene oxides such as propylene oxide and/orethylene oxide, secondary/tertiary amines, silaamines havingcarbon-silicon bonds (2,2,4-trimethyl-2-silamorpholine and1,3-diethylaminomethyltetramethyldisiloxane), nitrogen-containing bases(such as tetraalkylammonium hydroxides), alkali metal hydroxides (suchas sodium hydroxide, alkali metal phenoxides such as sodium phenoxide),alkali metal alkoxides (such as sodium methoxide), and/orhexahydrotriazines.

The reaction between NCO groups and Zerewitinoff-active hydrogen atoms,in a manner known per se, is greatly accelerated by lactams andazalactams as well, with initial formation of an associate between thelactam and the compound having acidic hydrogen.

It is also possible to use organic metal compounds, especially organictin and/or bismuth compounds, as catalysts. Useful organic tin compoundsinclude, as well as sulphur compounds such as di-n-octyltin mercaptide,preferably tin(II) salts of carboxylic acids such as tin(II) acetate,tin(II) octoate, tin (II) ethylhexoate and tin(II) laurate, and thetin(IV) compounds, for example dibutyltin oxide, dibutyltin dichloride,dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate ordioctyltin diacetate. Organic bismuth catalysts are described, forexample, in patent application WO 2004/000905.

It is of course possible to use any of the catalysts mentioned above asmixtures. Of particular interest in this context are combinations oforganic metal compounds and amidines, aminopyridines orhydrazinopyridines.

The catalysts are generally used in an amount of about 0.001% to 10% byweight, based on the total amount of compounds having at least twohydrogen atoms reactive toward isocyanates.

c) Surface-active additives such as emulsifiers and foam stabilizers

Useful emulsifiers include, for example, the sodium salts of castor oilsulphonates or salts of fatty acids with amines, such as diethylammoniumoleate or diethanolammonium stearate. It is also possible to use alkalimetal or ammonium salts of sulphonic acids as surface-active additivesas well, for instance of dodecylbenzenesulphonic acid ordinaphthylmethanedisulphonic acid or of fatty acids such as ricinoleicacid or of polymeric fatty acids.

Useful foam stabilizers include particularly polyether siloxanes,especially water-soluble representatives. The structure of thesecompounds is generally such that a copolymer of ethylene oxide andpropylene oxide is bonded to a polydimethylsiloxane radical. Ofparticular interest are polysiloxane-polyoxyalkylene copolymers withmultiple branching via allophanate groups.

d) Reaction retardants

Useful reaction retardants include, for example, acidic substances (suchas hydrochloric acid or organic acid halides).

e) Additives

Useful PU additives include, for example, cell regulators of the typeknown per se (such as paraffins or fatty alcohols) ordimethylpolysiloxanes, and also pigments or dyes and flame retardants ofthe type known per se (for example tris(chloroethyl) phosphate,tricresyl phosphate or ammonium phosphate and polyphosphate), and alsostabilizers against ageing and weathering influences, plasticizers andfungistatic and bacteriostatic substances, and also fillers (such asbarium sulphate, kieselguhr, carbon black or precipitated chalk).

Further examples of surface-active additives and foam stabilizers, andalso cell regulators, reaction retardants, stabilizers, flame-retardantsubstances, plasticizers, dyes and fillers, and also fungistatic andbacteriostatic substances, for optional additional use in accordancewith the invention are known to those skilled in the art and aredescribed in the literature.

EXAMPLES Component A-1

Linear polycarbonate based on bisphenol A having a weight-averagemolecular weight M_(w) of 26 000 g/mol.

Component A-2

Linear polycarbonate based on bisphenol A having a weight-averagemolecular weight M_(w) of 20 000 g/mol.

Component B-1

ABS emulsion polymer having an acrylonitrile:butadiene:styrene ratio of14:47:39% by weight and a median particle size d₅₀ of the graft base of315 nm, determined by ultracentrifuge measurement.

Component B-2

ABS emulsion polymer having an acrylonitrile:butadiene:styrene weightratio of 12:57:31% by weight and a median particle size d₅₀ of the graftbase of 340 nm, determined by ultracentrifuge measurement.

Component B-3

Rubber-free copolymer, prepared in a bulk polymerization process, from76% by weight of styrene and 24% by weight of acrylonitrile, having aweight-average molecular weight M_(W) of 130 000 g/mol (determined byGPC with polystyrene as standard).

Component C-1

Bisphenol A-based oligophosphate with phosphorus content 8.9%.

Component C-2

Resorcinol-based oligophosphate

To determine the reported number-average N values of components C-1 andC-2, the proportions of the oligomeric phosphates were first determinedby HPLC measurements:

Column type: LiChrosorp RP-8

Eluent in gradient: acetonitrile/water 50:50 to 100:0

Concentration: 5 mg/ml

The proportions of the individual components (mono- and oligophosphates)were then used to calculate the number-weighted N averages by knownmethods.

Component D-1

Pentaerythrityl tetrastearate is commercially available as Loxiol VPG861 from Emery Oleochemicals.

Component D-2

Irganox® B900

Mixture of 80% by weight of Irgafos® 168 (tris(2,4-di-tert-butyl)phenylphosphite) and 20% by weight of Irganox® 1076 (octadecyl3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (BASF, Germany).

Component D-3

Blendex 449: pulverulent PTFE preparation from General ElectricPlastics, consisting of 50% by weight of PTFE, present in an SANcopolymer matrix.

Reactive Polyurethane Coating System

The polyurethane coating system used was a mixture of Desmophen® XP 2488(polyol component) and Desmodur® N3600 (polyisocyanate component), bothfrom Bayer MaterialScience AG, Leverkusen, Germany, in a mixing ratio of1:1.7 parts by weight.

Desmophen® XP 2488 is a branched polyester polyol having a viscosity toDIN 53019 of 13 250 mPa·s at 20° C., a density to DIN 51757 of 1.12g/cm³ at 20° C. and an OH content of 16.0%.

Desmodur® N3600 is an aliphatic isocyanate based on hexamethylenediisocyanate having an NCO content to DIN EN ISO 11909 of 23.5% byweight, a viscosity at 23° C. to DIN EN ISO 3219/A.3 of 1200 mPa·s and adensity at 20° C. to DIN EN ISO 2811 of 1.16 g/cm³.

The crosslinking of the polyurethane coating system was catalysed with adibutyltin dilaurate (DBTL) commercially available from OMG BorchersGmbH, Langenfeld. The amount added was 0.5 part by weight based on thesum total of polyol component and polyisocyanate component.

Production and Characterization of the Polycarbonate MouldingCompositions

In a twin-screw extruder (ZSK-25) (from Werner and Pfleiderer), thefeedstocks listed in Table 1 are compounded at a speed of 220 rpm andwith a throughput of 20 kg/h at a melt temperature in the range from 260to 280° C. and pelletized after cooling and solidification of the meltof the compound.

The pellets resulting from the particular compounding operation areprocessed in an injection-moulding machine (from Arburg) at a melttemperature of 260° C. and a mould temperature of 80° C. to give testspecimens of dimensions 80 mm×10 mm×4 mm.

Unless stated otherwise, the parameters specified in the presentapplication are determined by the following methods:

The ductility of the moulding compositions is assessed using the notchedimpact resistance value a_(k) measured on these test specimens to ISO180-1A at 23° C.

The ductility of the moulding compositions is assessed using the impactresistance value a_(n) measured on these test specimens to ISO 180-1U at23° C.

Heat distortion resistance is assessed using the Vicat B120 valuemeasured on these test specimens to ISO 306.

Modulus of elasticity is measured in a tensile test to ISO 527-1, -2with a extension rate of 1 mm/min.

The flame retardancy class was determined on test specimens having athickness of 1 mm to UL94-V.

The composite adhesion between the substrate composed of polycarbonatecomposition and the polyurethane skin is determined on strip sampleshaving a width of 20 mm which were sawn out of the partially PU-coated2-component composite sheets thus produced, by a floating roller test toDIN EN 1464 with a testing speed of 100 mm/min.

Production of the Composite Components

Partially surface-coated mouldings having a projected area of 412 cm²were produced in an injection-moulding machine in an injection mouldhaving two cavities (a substrate-side cavity and a polyurethane-sidecoating cavity which was connected to an RIM system). The compositecomponent was a sheetlike component composed of thermoplastic polymer(carrier), the surface of which had been partly coated with apolyurethane layer. The wall thickness of the carrier moulding was about4 mm. The polyurethane layer thickness was 200 μm.

The process according to the invention for producing the inventivecomposite components described in the examples is shown in FIG. 1 forbetter illustration.

In the first process step, the carrier moulding was produced. For thispurpose, thermoplastic polymer pellets of the compositions as describedin Table 1 were melted in an injection-moulding barrel and injected at atemperature of 270° C. into the first mould cavity of the closed mould(steps 1 and 2 in FIG. 1). This mould cavity was heated to a temperatureof 80° C. After the hold-pressure time and cooling time, which led tothe solidification of the carrier, had elapsed, the mould was opened inthe second process step (step 3 in FIG. 1). This was done by holding thecarrier component produced on the ejector side of the injection mouldand moving it from the carrier position (step 3 in FIG. 1) together withthe mould core into the coating position using a slider (step 4 in FIG.1). Thereafter, the injection mould was closed again (step 5 in FIG. 1),a clamping force for a maximum pressure of 200 bar was applied and, inthe third process step, the solvent-free reactive polyurethane system(see above) was injected into the coating cavity under a pressure ofabout 30 bar (step 6 in FIG. 1). This was done by conveying the tworeactive components of the polyurethane coating system from the RIMsystem into a high-pressure countercurrent mixing head and mixing themtherein prior to injection. The PU-side cavity was heated to atemperature of 80° C. After the end of the injection, the injectionnozzle of the polyurethane mixing head was sealed by means of ahydraulic cylinder under a pressure of 50 bar at first, in order toprevent backflow of the coating material. After the reaction and coolingtime had elapsed, in the fourth process step, the mould was opened oncemore (step 7 in FIG. 1) and the coated moulding was demoulded (step 8 inFIG. 1).

Table 1 shows the influence of the carrier material compositions on theadhesion between the layers of the composite component.

The proportions of the components are reported in parts by weight.

TABLE 1 Component Unit Comparison 1 Example 1 Example 2 Comparison 2Example 3 A-1 54.71 73.10 37.15 42.21 71.82 A-2 9.83 10.15 36.54 35.2222.80 B-1 12.66 B-2 5.08 9.11 9.11 3.04 B-3 10.03 C-1 12.77 11.68 17.210.00 2.33 C-2 13.46 D-1 0.41 0.41 0.40 0.40 0.53 D-2 0.10 0.10 0.10 0.100.10 D-3 0.81 1.02 0.71 0.71 0.81 Polybutadiene content based on % 5.72.8 5.1 5.1 1.7 components A to C Butadiene-free vinyl (co)polymercontent % 16.9 2.2 4.0 4.0 1.3 based on components A to C Adhesion N/mm0.80 >7.00 2.42 3.47 >7.00 Izod notched impact resistance 23° C. kJ/m²29 30 30 25 45 Izod impact resistance 23° C. kJ/m² n.f. n.f. n.f. n.f.n.f. Modulus of elasticity from tensile test 23° C. MPa 2700 2700 27002700 2400 Vicat ° C. 99 108 93 90 136 UL94-V/1.0 mm Class failed V0 V0V0 V1 n.f.: No fracture Adhesion values >7 N/mm mean that thepolyurethane layer cannot be detached from the thermoplastic withoutdestruction.

As apparent from Table 1, Inventive Examples 1-3 exhibit not only adistinct improvement in adhesion to the polyurethane system but alsoconstantly high or improved toughness and high heat distortionresistance in combination with excellent flame retardancy. The optimalcombination of properties is achieved only when the polybutadienecontent based on components A+B+C is within the inventive range and, atthe same time, the content of butadiene-free vinyl (co)polymer islikewise within the inventive range. If, as in Comparative Example 1,the polybutadiene content and the butadiene-free vinyl (co)polymercontent are both exceeded, the adhesion does not reach the levelrequired in industry. Moreover, the required flame retardancy is notachieved. If, as in Comparative Example 2, a noninventive flameretardant is used, heat distortion resistance and notched impactresistance do not achieve the required level.

Particularly preferred moulding compositions are those for which theVicat temperature exceeds 100° C.

1. A composition comprising A) 30 to 45 parts by weight of at least one polymer selected from the group consisting of aromatic polycarbonate and aromatic polyester carbonate, B) 32 to 54 parts by weight of at least one polyalkylene terephthalate, optionally a polybutylene terephthalate, C) 16 to 23 parts by weight of at least one mixture comprising at least one polybutadiene-based graft polymer and at least one butadiene-free vinyl (co)polymer, D) 0.1 to 20.0 parts by weight (based in each case on the sum total of components A to C) of at least one polymer additive, where the polybutadiene content based on the sum total of the parts by weight of components A to C is 8% to 18% by weight, and where the total content of butadiene-free vinyl (co)polymer from component C based on the sum total of the parts by weight of components A to C is 3% to 12% by weight, and where the sum total of the parts by weight of components A to C in the polycarbonate composition is normalized to
 100. 2. A composition according to claim 1, wherein A) 32 to 45 parts by weight of at least one polymer selected from the group consisting of aromatic polycarbonate and aromatic polyester carbonate, B) 32 to 50 parts by weight of at least one polyalkylene terephthalate, optionally a polybutylene terephthalate, C) 17 to 22 parts by weight of at least one mixture comprising at least one polybutadiene-based graft polymer and at least one butadiene-free vinyl (co)polymer, D) 0.2 to 15.0 parts by weight (based in each case on the sum total of components A to C) of at least one polymer additive, where the polybutadiene content based on the sum total of the parts by weight of components A to C is 9% to 17% by weight, and where the total content of butadiene-free vinyl (co)polymer from component C based on the sum total of the parts by weight of components A to C is 4% to 11% by weight, and where the sum total of the parts by weight of components A to C in the polycarbonate composition is normalized to
 100. 3. A composition according to claim 1, comprising A) 35 to 45 parts by weight of at least one polymer selected from the group consisting of aromatic polycarbonate and aromatic polyester carbonate, B) 32 to 45 parts by weight of at least one polyalkylene terephthalate, optionally a polybutylene terephthalate, C) 18 to 21 parts by weight of at least one mixture comprising at least one polybutadiene-based graft polymer and at least one butadiene-free vinyl (co)polymer, D) 0.3 to 10.0 parts by weight (based in each case on the sum total of components A to C) of at least one polymer additive, where the polybutadiene content based on the sum total of the parts by weight of components A to C is 10% to 16% by weight, and where the total content of butadiene-free vinyl (co)polymer from component C based on the sum total of the parts by weight of components A to C is 5% to 10% by weight, and where the sum total of the parts by weight of components A to C in the polycarbonate composition is normalized to
 100. 4. A composition according to claim 1 wherein component C comprises C.1 5% to 60%, optionally 15% to 58% and optionally 20% to 55% by weight, based on component C.1, of at least one vinyl monomer on C.2 95% to 40%, optionally 85% to 42% and optionally 80% to 45% by weight, based on component C.1, of one or more polybutadiene-based graft bases.
 5. The composition according to claim 4, wherein component C.1 comprises mixtures of C.1.1 50 to 99 parts by weight, based on C.1, of vinylaromatics and/or ring-substituted vinylaromatics optionally styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, and/or (C₁-C₈)-alkyl methacrylates optionally methyl methacrylate, ethyl methacrylate, and C.1.2 1 to 50 parts by weight, based on C.1, of vinyl cyanides (unsaturated nitriles optionally acrylonitrile and methacrylonitrile) and/or (C₁-C₈)-alkyl (meth)acrylates such as methyl methacrylate, n-butyl acrylate, t-butyl acrylate, and/or derivatives (optionally anhydrides and imides) of unsaturated carboxylic acids, optionally maleic anhydride and N-phenylmaleimide.
 6. A composition of claim 1, wherein component D comprises one or more of thermal stabilizers, demoulding agents, colourants and UV absorbers.
 7. A composition of claim 1, wherein component B is polybutylene terephthalate.
 8. A composite component comprising a) a carrier composed of a thermoplastic composition according to claim 1 b) at least one polyurethane layer selected from the group of coating materials, foams and compact skins, comprising at least one polyisocyanate component, at least one polyfunctional H-active compound, and optionally at least one polyurethane additive and/or processing aid, And having a molar ratio of NCO- to H-active groups of 1:1 to 1.1:1.
 9. A composite component according to claim 8, wherein the polyurethane layer is a coating material having a layer thickness of 50-300 μm.
 10. A composite component according to claim 8, wherein the polyurethane layer is a foam having a layer thickness of 1 mm to 1 cm.
 11. A composite component according to claim 8, wherein the polyurethane layer is a compact skin having a layer thickness of 1 mm to 4 mm.
 12. A process for producing a composite component according to claim 8, wherein the polyurethane layer has been produced by full polymerization of a reactive polyurethane raw material mixture comprising at least one polyisocyanate component, at least one polyfunctional H-active compound, and optionally at least one polyurethane additive and/or processing aid, in direct contact with the carrier which has been shaped beforehand from the thermoplastic composition and solidified.
 13. A process for producing a composite component according to claim 8, (i) injecting a melt of the thermoplastic composition into a first mould cavity and then cooling, (ii) transferring the cooled thermoplastic component into a larger cavity and producing a defined gap thereby, (iii) the gap which thus results between the thermoplastic component and the mould surface of the enlarged cavity is injected with a reactive polyurethane raw material mixture comprising at least one polyisocyanate component, at least one polyfunctional H-active compound, and optionally at least one polyurethane additive and/or processing aid, the polyurethane raw material mixture polymerizing fully in direct contact with the surface of the thermoplastic carrier to give a compact polyurethane layer or to give a polyurethane foam layer, (iv) the composite component is demoulded from the mould cavity, wherein (i) to (iv) following one another in immediate succession.
 14. The process according to claim 13, wherein, in (iii) the surface of the injection mould in contact with the thermoplastic composition is heated to a temperature in the range of 60 to 90° C. and the surface of the injection mould in contact with the reactive polyurethane mixture to a temperature in the range of 60 to 90° C.
 15. A composite component according to claim 8 capable of being used as an interior or exterior component of a rail vehicle, aircraft or motor vehicle or of an electrical/electronic component. 